Trimmer mechanism for sewing machines



July 1943- I. J. FREY TRIMMER MECHANISM FOR SEWING MACHINES 3 Sheets-Sheet l Filed Sept. 24, 1940 clam/M1 July 6, 1943. J. FREY TRIMMER MECHANISM FOR SEWING MACHINES :5 Sheets-Shee t 2 Filed Sept. 24, 1940' grwc'wtob Irvin Cl Frey July 6, 1943. I. J. FREY 2,323,750

TRIMMER MECHANISM FOR SEWING MACHINES Patented July 6, 1943 TRIMMER MECHANISM FOR SEWING MACHINES Irvin John Frey, Lakewood, Ohio, assignor to The Singer Manufacturing Company, Elizabeth, N. J a corporation of New Jersey Application Septcmber 24, 1940, Serial No. 358,045 27 Claims. (c1. 112 125 This invention relates to trimmer-mechanisms of sewing machines and is in the nature of an improvement in the trimming mechanism disclosed in the United States patent of F. M. Card, No. 2,105,346, Jan. 11, 1938.

A primary object of the present-invention is to provide a simplified form of actuating mechanism for the knife-bar ofa trimmer-mechanism and, more particularly, a trimmer-mechanism of a sewing machine in which the needle and the trimmer-knife are adapted to be operated at relative frequencies having a ratio variable at will during the operation of the sewing machine.

A further object of the invention is to provide means of simple construction for throwing a trimmer-knife into and out of effective action. Other and more specific objects of the invention will be apparent from the following description and claims.

The invention consists in the trimmer knifebar supporting and actuating mechanism, and the knife-bar operation controlling means hereinafter described in connection with the accompanying drawings which illustrate a preferred embodiment of the invention and in which:

Fig. 1 is a rear side elevation of a sewing machine provided with the improved trimmer actuating mechanism, the sewing machine frame and the presser-mechanism of the machine being shown partly broken away. Fig. 2 is a top plan view of the trimmer actuating mechanism, with the belt-guard partly broken away and with the bracket-arm standard of the machine shown in section. Fig. 3 is an enlarged front side elevation, partly in section, of the trimmer bracket and the mechanism supported thereby. Fig. 4 is an enlarged front end elevation, partly in section, of the knife-bar reciprocating mechanism, as viewed in a direction normal to the longitudinal axis of the knife-bar. Fig. 5 represents an enlarged perspective view of the toggle-link knife-bar actuating pitman and of the parts directly associated therewith, in the toggle-broken position of said pitman.

The sewing machine illustrated in the drawings has a frame including a base-standard I supporting the arm-standard 2 of a bracket-arm 3 terminating in a head 4 which overhangs an upright work-supporting post 5.

Journaled in the bracket-arm 3 to extend 1ongitudinally thereof is a horizontally disposed main actuating or needle-reciprocating shaft 6 (shown in dotted lines in Fig. 1 said shaft carrying at one end a combined belt-pulley and balance-wheel 1 connected to any usual or Suit able power-source by means of which the sewing machine is brought into and controlled as to its speed of operation. The opposite end of the shaft 6 is connected in any usual or suitable manner (not shown) to actuate a vertically reciprocatory needle-bar 8 carrying at its lower end an eye-pointed needle 9.

Attached to a flattened portion ill of the under side of the bracket-arm 3, by bolts II, is a baseblock l2, from which extends a knife-bar bracket 93 having a vertically inclined portion thereof provided with vertically spaced bearing-lugs I4 and I5. The bearing-lugs I4, l5, are provided with apertures which are alined in a vertically inclined direction, the upper bearing-lug l4 having a bearing-bushing l6, and the lower bearinglug IS a bearing-bushing I'I.

Journaled for endwise reciprocation in the bearing-bushings I6 and I1 is a knife-bar I8, to the lower end of which a knife-holder plate I9 is adjustably secured by a screw 20. Adjustably will attached by screws 2| to the knife-holder plate I9 is the vertically slotted shank of a trimmerknife 22 provided with a cutting-edge 23.

A collar 24 is attached by screws 25 to the knife-bar l8 between the bracket-lugs l4 and I5,

said collar having a flat sided lateral extension 26 slidably disposed in a vertically inclined slot 21 formed in a fixed guide-block 28. The guideblock 28 is secured by screws 29 upon the rear side of the knife-bar bracket l3 and functions to restrain the knife-bar 18 against turning in its bearings. The slot 21 is open at the lower end of the guide-block 28 andmay be adjusted as to width by means of a bolt 21; thereby providing for taking up wear.

Threaded into the collar extension 26 is a shoulder-screw 30 pivotally embraced by the apertured boss 3i at one end of a toggle-link 32, said screw 30 also serving to secure an angular A spring 34 has one end connected to the plate 33 and its opposite end anchored to a post 35 carried by a bracket 36. The bracket 36 has a base 31 secured by screws 38 upon the base-block l2 of the knife-bar bracket l3, said bracket 36 being provided at the free end portion of the bracket-arm 3 with laterally spaced and horizontally apertured bearing-lugs 39 and 40 disposed in proximity to the head 4 of the machine bracket-arm and at the rearward side of the bracket-arm.

The bracket-lugs 39 and 40 are provided with needle-roller bearings M, in which is rotatably journaled a knife-bar actuating shaft 42 having its axis of rotation transverse to that of the needle-reciprocating shaft 6. The axis of rotation of the shaft 6 is, preferably, also disposed in a plane containing the longitudinal axis of the knife-bar l8. A pulley 43 is secured by screws 44 upon the shaft 42 between the bracket-lugs 39 and 40; the pulley 43 preferably having a plurality of belt-grooves of different effective diameters.

The end of the shaft 42 proximate to the head 4 of the bracket-arm is provided with an eccentric member or crank-pin 45 embraced by a strap 46 of a toggle-link 41, needle-roller-bearings 48 being preferably interposed between the crankpin 45 and the link-strap 46. The toggle-link 41 is provided between its ends with laterally spaced and apertured ears 49 in which is disposed a pivot-pin 59; and secured by a screw upon the pivot-pin 59 is an apertured end of the toggle-link 32 which is connected to the knifebar [8.

The pivotal axes 30 and 51] of the toggle-links 32 and 41 are substantially parallel, whereby said links may be brought into toggle-straightened relation as illustrated in Figs. 3 and 4 of the drawings, or may be brought into a togglebroken relation as illustrated in Fig. 5. The lower portion 41' of the toggle-link 41 which extends beyond the link-ears 49 is adapted to engage the toggle-link 32, thereby limiting relative movement of the links 32, 41 into togglestraightened relation of said links. In order to maintain the links 32, 41 releasably in togglestraightened relation, a latch-plate 52 is secured by screws 53 to the link-extension 41, said latch-plate having a pair of bent spring-prongs 54 adapted to engage the link 32.

It will be understood from the foregoing description that the links 32, 41, in the togglestraightened relation thereof, constitute a pitman for reciprocating the knife-bar l8 from the crank-pin 45. To provide convenient means for at will breaking the toggle during the operation of the machine, a. hand-lever 55 is fulcrumed intermediate its ends upon a supporting plate 56 by means of a pivot-bolt 5'l, the supporting plate 56 being secured upon the rear face of the knife-bar guide-block 28 by the fastening screws 29 therefor. The lower or depending arm of the lever 55 is conveniently accessible below the machine bracket-arm 3 for swinging said lever in opposite directions.

The upper arm of the hand-lever 55 is dis posed for engagement with a pin 58 extending from a curved arm 59 pivotally hung upon the bracket 36 by means of a stud-screw 60, said stud-screw 66 being threaded into the lug of the bracket 36 at a point substantially vertically above the knife-bar actuating shaft 42. The free end of the arm 59 is formed with an elongated slot 6! loosely entered by one end of the pivot-pin 50 whereby, upon swinging movement of the hand-lever 55 in one direction, the arm 59 is actuated to release the latch-prongs 54 from the link 32 and to bring the links 32, 47 into the toggle-broken relation thereof illustrated in Fig. 5 of the drawings. The movement of the links 32, 41 into toggle-broken relation, initiated by operation of the hand-lever 55, is materialy assisted and may be entirely completed by the action of the spring 34 which yieldingly biases the knife-bar 18 into a raised inoperative position thereof.

The knife-bar l8 may also be depressed into the operative position thereof and to straighten the toggle-links 32, 41, by actuation of the handlever 55. To that end, the upper arm of t hand-lever 55 is provided with a finger 55' adapted to engage the upper protruding end of a plunger 62 slidably disposed in a. longitudinal bore 63 of the knife-bar. A coil-spring 64 is interposed between the plunger 62 and the bottom wall of the bore 63. Upward movement of the plunger 62, under the action of the spring 64, is limited by a stop-pin 65 carried by the knife-bar and extending through a slot 66 formed in the plunger 62, Upon operation of the hand-lever 55 in a direction to depress the knife-bar l8, the finger 55 of said lever engages the plunger 62 which transmits its movement to the knife-bar through the spring 64. The knife-bar is thereby depressed sufificiently to straighten and latch the toggle-links 32, 41, and should this be effected during the operation of the machine, the resultant reciprocation of the knife-bar forces the hand-lever 55 to swing in a direction away from plunger 62. The shock which might thus be transmitted to the operators hand through the hand-lever 55 is in the main absorbed by the spring 64, and the trimmer-bar may therefore be at will thrown into and out of action during the operation of the machine. I The curved arm 59, which is actuated by the hand-lever 55 to disable the knife-bar actuating mechanism, is provided with stepped notches 61 and 68 alternately engaged by the V-shaped portion of a latch-spring 69 to retain said arm 59 yieldingly in the positions thereof corresponding to toggle-straightened and toggle-buckled positions of the links 32, 41. The spring 69 is secured by screws 10 upon the bracket 36. The hand-lever 55 is preferably limited in its swinging movement in a clockwise direction as viewed,

in Fig. 3, by a stop-pin H extending from the supporting-plate 56.

The pulley 43 of the knife-bar actuating shaft 42 is connected by a belt 12 to a doublegrooved pulley 73 carried by the rotor-shaft 14 of an electric motor 15. The electric motor is supported upon an angular bracket 16 adjustably secured by screws 11 upon the rear side of the base-standard l of the machine, the adjustment being provided primarily for taking up slack in the belt 12. The rotor-shaft '14 of the electric motor extends transversely of the needle-reciprocating shaft 6, thus providing for direct connections between the shafts 42 and 14 by beltruns extending lengthwise of the bracket-arm 3 and disposed at the rearward side of said bracket-arm. This comprises a very simple form of knife-bar driving means.

' By driving the knife-bar separately, as herein described, the relative frequencies of reciprocation of the needle-bar and the knife-bar may be readily varied during the operation of the machine, as for example by controlling the speed of operation of the sewing machine by the usual power transmission means. This is highly advantageous when eifecting trimming of sharply curved work as will be self-evident. The frequency of reciprocation of the knife-bar may also be changed by shifting the belt 12 from one to the other of the pulley grooves. When it is desired to employ the sewing machine for stitching purposes, without trimming the work, the motor may be disconnected from its power source by any usual or suitable means, as for example, by means of the switch 18. Likewise, the machine may be employed for trimming purposes alone, as for example, by removing the needle 9.

As a safety measure, the belt is preferably housed by a channeled belt-guard 19 attached by screws 80 to the base-block 2 of the knife-bar bracket l3. The belt-guard 19 is partly cut away to provide a slot 8| in the vertical side wall thereof to afford clearance for the free end portion of the bracket 36. It will be understood from the foregoing description that the entire driven portion of the trimming mechanism, together with the belt-guard 19, comprises a unit assembly adapted to be detachably secured to the sewing machine. As the loop-taking means of the sewing machine complemental to the needle in the formation of stitches, the work-feedingmechanism, and the ledger-blade complemental t the reciprocating knife may be of any usual or suitable construction, it is deemed unessential to describe the same herein.

Having thus set forth the nature of the invention what I claim herein is:

1. In a sewing machine having stitoh-forining mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitch-forming mechanism including a reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its axis of rotation transverse to the rotationaxis of said needle-reciprocating shaft, a pitman directly pivoted to said knife-bar and having a strap embracing said eccentric, and driving means operable independently of said needlereciprocating shaft for rotating said knife-bar actuating eccentric.

, 2. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle reciprocating shaft, and a trimmer mechanism including a reciprocatory knife-bar associated with said stitch-forming mechanism, theimprovement which consists in the provision of a rotary knife-bar actuating shaft having its axis of rotation transverse to the rotation-axis of said needle-reciprocating shaft, an eccentric carried by said knife-bar actuating shaft, a pitman directly pivoted to said knife-bar and having a strap embracing said eccentric, an electric motor operable independently of said needle-reciprocating shaft, and a driving belt connecting said electric motor and knife-bar actuating shaft.

3. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, and a trimmer mechanism associated with said stitch-forming mechanism, said trimmer mechanism including a reciprocatory knife-bar having a path of reciprocation inclined to the path of needle-reciprocation, the improvement which consists in the provision of a rotary eccentric having its axis of rotation disposed in a plane containing the longitudinal axis of said knifebar, and a pitman having one end pivotally connected to said knife-bar and having at its other end a strap embracing said eccentric.

4. In a sewing machine having a frame including a bracket-arm formed with a free end, stitch-forming mechanism'including a reciprocatory needle journaled in the free end portion of said bracket-arm, and a trimmer mechanism associated with said stitch-forming mechanism, said trimmer mechanism including a reciproca tory knife-bar having a path of reciprocation inclined to the path of needle-reciprocation, the improvement which consists in the provision of a rotary actuating element, a pitman having one end directly pivoted to said knife-bar and pro vided at its other end with a strap embracing said eccentric, driving means for rotating said actuating element, and means for at will disabling said pitman from eiiective action during the operation of the machine.

5. In a sewing machine having a frame including a bracket-arm formed with a free end, stitchforming mechanism including a reciprocatory needle journaled in the free end portion of said bracket-arm, and a trimmer mechanism associated with said stitch-forming mechanism, said trimmer mechanism including a reciprocatory knife-bar having a path of reciprocation inclined to the path of needle-reciprocation, the improvement which consists in the provision of a rotary actuating element, a pitman having one end directly pivoted to said knife-bar and provided at its other end with a strap embracing said eccentric, and driving means for rotating said actuating element independently of the operation of the sewing machine.

6. Trimmer mechanism for sewing machines comprising, a reciprocatory knife-bar, a rotary knife-bar actuating eccentric, a pair of togglejointed links operatively connecting said eccentric to said knife-bar, one of said links having a pivotal connection with said knife-bar and the other of said links having a strap embracing said eccentric, latching means for releasably maintaining said links in toggle-straightened relation, a manually operable lever engageable with said knife-bar for shifting said knife-bar from retracted to operative positions thereof and for effecting straightening of the toggle-links from toggle-buckled relation thereof, and a pivotal arm operable by said lever and operatively connected to said links for buckling said links out of toggle-straightened relation, thereby retracting said knife-bar from operative position.

7. In a sewing machine having a frame including a bracket-arm formed with a free end, stitch-forming mechanism including a reciprocatory needle-bar journaled in the free end portion of said bracket-arm, and mechanism associated with said stitch-forming mechanism including an actuated member, the improvement which consists in the provision of a rotary actuating eccentric disposed at the free end portion of said bracket-arm, said actuating eccentric having its axis of rotation transverse to the length of said bracket-arm, means for actuating said member from said eccentric comprising a pair of toggle-jointed links, one of said links having a pivotal connection with said actuated member and the other of said links being provided with a strap embracing said eccentric, releasable means for maintaining said links in togglestraiglitened operative relation, means operable at will during the operation of the machine for disabling said links, and driving means for rotating said eccentric.

8.- In a sewing machine having a frame in cluding a bracket-arm formed with a free-end, a reciprocatory needle-bar journaied in the free end. portion of said bracket-arm, and a reciprocatory trimmer-knife bar, the improvement which consists in the provision at the free end portion of said bracket-arm of a rotary actuating element having its axis of rotation transverse to the length of said bracket-arm, operative connections with said actuating element for reciprocating said trimmer-knife bar, an electric motor having its rotor shaft disposed substantially parallel to the axis of rotation of said eiement and driving connections for rotating said element from said motor including a belt having its runs extending lengthwise of said bracket-arm.

9. A trimmer-mechanism unit assembly for sewing machines, comprising a supporting bracket adapted to be detachably secured to the frame of a sewing machine, a trimmer-knife bar journaled for endwise reciprocation in said bracket, a rotary eccentric journaled in said bracket and having its axis of rotation disposed in a plane containing the longitudinal axis of said knifebar, and a pitman pivotally connected to said knife-bar, said pitman having a strap embracing said eccentric.

10. A trimmer-mechanism unit assembly for sewing machines, comprising a supporting bracket adapted to be detachably secured to the frame of a sewing machine. a trimmer-knife bar journaledfor endwise reciprocation in said bracket, a rotary eccentric journaled in said bracket, 2. pair of toggle-jointed links operatively connecting said eccentric and said knifebar, and means for releasably maintaining said links in togglestraightened relation.

11. A trimmer mechanism unit assembly for sewing machines, comprising a supporting bracket adapted to be detachably secured to the frame of asewing machine, a trimmer-knife bar journaled for endwise reciprocation in said bracket, a rotary shaft journalecl in said bracket for retation about an axis substantially normal to the longitudinal axis of said knife-bar, an actuating element carried by said shaft, and operative connections for reciprocating said knife-bar from said actuating element.

12. A trimmer-mechanism unit assembly for sewing machines, comprising a supporting bracket adapted to be detachably secured to the frame of a sewing machine, a trimmer-knife bar journaled in said bracket for endwise reciprocation, a rotary shaft journaled in said bracket, a belt pulley carried by said shaft, an eccentric carried by said shaft, and a pitman connection between said eccentric and knife-bar.

13. A trimmer-mechanism unit assembly for sewing machines, comprising a supporting bracket adapted to be detachably secured to the frame of a sewing machine, a trimmer-knife bar journaled in said bracket for endwise reciprocation, a rotary eccentric journaled in said bracket, a pitman connecting said eccentric and knife-bar, said pitman comprising a pair of toggle-jointed links releasably maintained in toggle-straightened relation, and manually operable means carried by said bracket for togglebreaking and toggle-straightening said links.

14. A trimmer-mechanism unit assembly for sewing machines, comprising a supporting bracket adapted to be detachably secured to the frame of a sewing machine, a trimmer-knife bar journaled in said bracket for endwise reciprocation, a rotary eccentric journaled in said bracket, a pitman connecting said eccentric and knife-bar, said pitman comprising a pair of toggle-jointed links releasably maintained in toggle-straightened relation, an arm pivotally mounted upon said bracket and disposed to effect buckling of the toggle-straightened links upon movement of said arm in one direction, and manually operable means carried by said bracket for actuating said arm.

15. A trimmer-mechanism unit assembly for sewing machines, comprising a supporting bracket adapted to be detachably secured to the frame of a sewing machine, a trimmer-knife bar journaled in said bracket for endwise reciprocation, a rotary eccentric journaled in said bracket, a pitman connecting said eccentric and knifebar, said pitman comprising a pair of togglejointed links releasably maintained in togglestraightened relation, a manually operable arm pivotally mounted upon said bracket and disposed to efiect buckling of the toggle-straightened links upon movement of said arm in one direction, and yieldable means for latching said arm in toggle-straightened and toggle-buckled positions of said links.

16. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitchforming mechanism including an endwise reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its axis of rotation transverse to the rotation-axis of said needle-reciprocating shaft and disposed in a plane containing the longitudinal axis of said knife-bar, a pitman having one end thereof directly pivoted to said knife-bar and having at its other end a strap embracing said eccentric, and means for rotating said eccentric.

1'7. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle reciprocating shaft, and a trimmer mechanism associated with said stitchforming mechanism including an endwise reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its axis of rotation transverse to the rotation-axis of said shaft, a pitman operatively connecting said eccentric and knife-bar and comprising a pair of togglelinks connected for pivotal movement relative to each other about an axis substantially parallel to the rotation-axis of said eccentric, said toggle-links being releasably maintained in togglestraightened relation, and means for rotating said eccentric.

18. In a sewing machine having stitch-forming mechanism includin a reciprocatory needle.

a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitchforming mechanism including an endwise reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its axis of rotation transverse'to the rotation-axis of said shaft, a pitman operatively connecting said eccentric and knife-bar and comprising a pair of toggle-links connected for pivotal movement relative to each other about an axis substantially parallel to the rotation-axis of said eccentric, said links being releasably maintained in toggle-straightened relation, means operable at will during the operation of the machine for buckling said togglelinks, thereby to disable said pitman, and means for rotating said eccentric.

19. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitchforming mechanism including an endwise reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its axis of rotation transverse to the rotation-axis of said shaft, a pitman operatively connecting said eccentric and knife-bar and comprising a pair of togglelinks pivotally connected together for movement relative to each other about an axis substantially parallel to the rotation-axis of said eccentric, said links being releasably maintained in togglestraightened relation, and driving means for rotating said eccentric independently of the operation of said needle-reciprocating shaft.

20. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitch-forming mechanism including an endwise reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its rotation-axis disposed in substantially the plane containing the longitudinal axis of said knife-bar, a pitman operatively connecting said eccentric and knife-bar, means for rotating said eccentric, and means operable at will during the operation of the machine for disabling said pitman.

21. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitch-forming mechanism including an endwise reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its rotation-axis disposed in substantially a plane containing the longitudinal axis of said knife-bar, a pitman operatively connecting said eccentric and knife-bar and comprising a pair of toggle-links pivotally connected together for movement relative to each other about an axis substantially parallel to the rotationaxis of said eccentric, said links being releasably maintained in toggle-straightened relation, and means for rotating said eccentric.

22. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitch-formin mechanism including an endwise reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its rotation-axis disposed in substantially a plane containing the longitudinal axis of said knife-bar, a pitman operatively connecting said eccentric and knife-bar and comprising a pair of toggle-links pivotally connected together for movement relative to each other about an axis substantially parallel to the rotation-axis of said eccentric, said links being releasably maintained in toggle-straightened relation, and driving means for rotating said eccentric independently of the operation of said needle-reciprocating shaft.

23. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitch-forming mechanism including an endwise reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its rotation-axis disposed in substantially a plane containing the longitudinal axis of said knife-bar, a pitman operatively connecting said eccentric and knife-bar and comprising a pair of toggle-links pivotally connected together for movement relative to each other about an axis substantially parallel to the rotation-axis of said eccentric, said links being releasably maintained in toggle straightened relation, driving means for rotating said eccentric independently of the operation of said needle-reciprocating shaft, and means operable at will during the operation of the machine for buckling said toggle-links, thereby to disable the pitman.

24. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitchforming mechanism including an endwise reciprocatory knife-bar, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its rotation-axis disposed in substantially a plane containing the longitudinal axis of said knife-bar, a pitman operative- 1y connecting said eccentric and knife-bar and comprising a pair of toggle-links pivotally connected together for movement relative to each other about an axis substantially parallel to the rotation-axis of said eccentric, said links being releasably maintained in toggle-straightened relation, means for rotating said eccentric, and means for buckling said toggle-links, thereby to disable said pitman.

25. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitchforming mechanism including an endwise reciprocatory knife-bar having a path of reciprocation inclined to the path of needle-reciprocation, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its axis of rotation transverse to the rotationaxis of said shaft and disposed in a plane containing the longitudinal axis of said knife-bar, operative connections for reciprocating said knife-bar from said eccentric, and means for r0- tating said eccentric.

26. In a sewing machine having stitch-forming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitchforming mechanism including an endwise'reciprocatory knife-bar having a path of reciprocation inclined to the path of needle-reciprocation, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its axis of rotation transverse to the rotation-axis of said shaft, a pitman pivotally connected to said knife-bar and having a strap embracing said eccentric, and means for rotating said eccentric independently of said needlereciprocating shaft.

27. In a sewing machine having stitch-dorming mechanism including a reciprocatory needle, a rotary needle-reciprocating shaft, and a trimmer mechanism associated with said stitchforming mechanism including an endwise reciprocatory knife-bar having a path of reciprocation inclined to the path of needle-reciprocation, the improvement which consists in the provision of a rotary knife-bar actuating eccentric having its axis of rotation transverse to the rotation axis of said shaft, a pitman operatively connecting said eccentric and knife-bar and comprising a pair of toggle-links connected for pivotal movement relative to each other about an axis substantially parallel to the rotation-axis of said eccentric, said toggle-links being releasably maintained in toggle-straightened relation, and means for rotating said eccentric.

IRVIN JOHN FREY. 

